In certain applications it may be necessary to generate a voltage signal having a voltage range greater than the safe operating voltage of the transistor technology being used. For example, in CMOS 65 nm technology, the voltage applied across the terminals of the transistors should generally not exceed 1.2 V, whereas it may be desired to generate a voltage signal having a greater voltage range.
A solution that has been proposed is to use a technique of cascoding transistors. However, while such a technique works well while the input voltage is static, transitions of the input voltage between low and high levels can cause spikes in the voltage across either or both of the cascoded transistors that correspond to an overvoltage, in other words a voltage exceeding the safe voltage limit of the transistor technology. While this may not result in an immediate failure of the transistors, over time there will a degradation in their performance, leading to a reduced life span.
There is thus a need in the art for a high voltage driver that prevents or at least partially reduces overvoltages, and that has a low surface area and/or relatively low power consumption.